JP3197804U - Fuel level sensor - Google Patents

Abstract

A fuel level sensor capable of preventing the occurrence of sparks in a circuit part and ignition and preventing malfunction of a mechanism part. A float 10 is installed inside a fuel tank Q. A magnet 22 is provided on the swing shaft 21 side of the float 10. The swinging shaft 21 and the magnet 22 constitute a mechanism unit 20. The mechanism unit 20 is protected by a protective cover 23. The mechanism unit 20 is installed inside the fuel tank Q. A circuit unit 30 including a hall element 31 is provided. The hall element 31 detects the angle of the magnet 22 interlocked with the float 10. The circuit unit 30 is accommodated in the substrate case 32. The circuit unit 30 is installed outside the fuel tank Q. [Selection] Figure 1

Description

  The present invention relates to a fuel level sensor that detects the level of gasoline, light oil, or the like in a fuel tank such as a transport device or a generator.

  As a conventional fuel liquid level sensor for automobiles, a liquid level sensor is known which detects a liquid level by converting the liquid level into a potential difference. For example, in the liquid level sensor described in Patent Document 1, a float arm 3 having a float 6 disposed at the tip, an arm holder 4 held on the base end side of the float arm 3, and the arm holder 4 And the contact piece 5 arranged on the surface.

  In this liquid level sensor, when the float 6 moves up and down due to fluctuations in the liquid level, the float arm 3 rotates within a predetermined angle range with the rotary shaft 3a as a fulcrum. By this rotation, the contact piece 5 slides on the resistor 7, and when the resistance value between one end of the resistor 7 and the contact point 5a of the contact piece 5 changes in the detection circuit, this is detected, A level signal indicating the liquid level fluctuation amount is taken out from the output terminal 8.

  Moreover, the liquid level detection apparatus described in Patent Document 2 is an apparatus configured to be in electrical contact by spring elasticity. That is, the float 20 linked to the fluctuation of the liquid level, the resistance plate 40 including the resistance patterns 42 and 43 and the conductor pattern 44, and the metal fixed to the back surface of the yoke 30 that slides linked to the fluctuation of the float. The device includes a contact 33 of the plate 32, and a terminal 50 for connecting one end 42a of the resistance pattern 42 and an external circuit.

  When the float 20 moves downward as the liquid level decreases, the yoke 30 also moves downward, and the contact 33 of the plate 32 fixed to the back surface of the yoke 30 slides downward on the conductor pattern 44, and each resistance. Each of the resistance values of the patterns 42 and 43 is sequentially added to increase the resistance value.

Japanese Patent Laid-Open No. 2003-4506 JP-A-9-5145

  However, in the conventional liquid level sensor where the electronic circuit is installed inside the fuel tank, a spark is generated in the electronic circuit due to some external factor or failure, or the spark ignites the fuel. There was a possibility.

  In addition, there is a possibility that sand iron or gravel from the civil engineering site may be mixed in the fuel tank used for construction machinery, etc. In the situation where the electronic circuit is exposed in the tank, there is gravel at the contact part of the contactor. There was also a problem that contact failure occurred due to pinching.

  Therefore, the present invention has been devised to solve the above-mentioned problems, and prevents the occurrence of a spark due to some external factor and the ignition of the spark to the fuel, and contains iron and gravel in the tank. Even so, it is an object of the present invention to provide a fuel level sensor that can prevent malfunction and failure of each part.

  In order to achieve the above object, the first means in the present invention is a fuel level sensor that detects the liquid level in accordance with the vertical movement of the float 10 installed in the fuel tank Q. A mechanism portion 20 is provided by a swing shaft 21 that pivotally supports the rod 11 and a magnet 22 provided at the end of the swing rod 11 on the swing shaft 21 side, and a substrate 33 installed outside the fuel tank Q. And the Hall element 31 mounted on the substrate 33, the circuit unit 30 is provided, and the mechanism unit 20 is installed inside the fuel tank Q, and at the Hall element 31 of the circuit unit 30 installed outside the fuel tank Q Thus, the angle of the magnet 22 interlocked with the float 10 is detected.

  In the second means, the mechanism unit 20 is installed in the fuel tank Q in a state of being accommodated in the protective cover 23, and the circuit unit 30 is in the state of being accommodated in the substrate case 32. It was installed outside Q.

  In the third means, the protective cover 23 and the substrate case 32 are formed of a resin excellent in oil resistance and slidability.

  As described in claim 1 of the present invention, the mechanical unit 20 is installed inside the fuel tank Q, and the circuit unit 30 is installed outside the fuel tank Q. Occurrence and ignition of this spark to the fuel can be prevented. Therefore, extremely safe use is possible.

  As in claim 2, by installing the mechanism unit 20 inside the fuel tank Q in a state of being housed in the protective cover 23, sand iron, gravel, etc. mixed in the fuel tank Q may cause malfunction of the mechanism unit 20. Parts failure can be prevented.

  In addition, by installing the circuit unit 30 outside the fuel tank Q in a state where it is housed in the substrate case 32, the circuit unit 30 can be reliably protected, and the fuel in the fuel tank Q and the iron sand on the civil engineering site can be protected. It prevents contamination of gravel.

  In addition, the mechanism unit 20 and the circuit unit 30 are installed separately inside and outside the fuel tank Q and function without being physically affected by each other, but the liquid level stabilized by the magnet 22 and the Hall element 31 is stable. Detection is possible.

  As in claim 3, the protective cover 23 and the substrate case 32 are formed of a resin excellent in oil resistance and slidability.

  As described above, according to the present invention, it is possible to prevent the occurrence of a spark due to an external factor and the ignition of the spark to the fuel, and also prevent malfunction or failure of each part even if sand iron or gravel is mixed in the tank. Achieved the initial goal of being able to.

1 is a schematic side view showing an embodiment of the present invention.

  The present invention is a liquid level sensor that detects the level of gasoline, light oil or the like as the float 10 installed in a fuel tank Q such as a transportation device or generator moves up and down.

  The basic configuration of the present invention includes a mechanism unit 20 installed inside the fuel tank Q and a circuit unit 30 installed outside the fuel tank Q.

  The mechanism unit 20 includes a swing shaft 21 that pivotally supports the swing rod 11 of the float 10 and a magnet 22 provided at the end of the swing rod 11 on the swing shaft 21 side. In the illustrated example, the swing shaft 21 and the magnet 22 are installed inside the fuel tank while being housed in the protective cover 23. At this time, the protective cover 23 is provided with a resin (POM or the like) excellent in oil resistance and sliding property.

  The illustrated float 10 has a configuration in which a swing rod 11 is pivotally supported on a swing shaft 21 so as to be swingable up and down, and a float 12 is provided at the tip of the swing rod 11. At this time, the float 12 excellent in oil resistance can be provided by using NBR as the material of the float 12.

  On the other hand, the circuit unit 30 installed outside the fuel tank Q is provided with a Hall element 31, and this Hall element 31 detects the angle of the magnet 22 interlocked with the float 10. That is, a magnetoelectric conversion method is adopted in which the angle of the magnet 22 is converted into a voltage and the liquid level in the fuel tank Q is detected.

  The illustrated circuit unit 30 is provided with a substrate 33 installed outside the fuel tank Q, and a Hall element 31 is mounted on the substrate 33. The circuit unit 30 is housed inside the substrate case 32 and is installed outside the fuel tank Q. At this time, the substrate case 32 is provided with a resin (POM or the like) excellent in oil resistance and sliding property.

  When the float 10 swings with the liquid level in the fuel tank Q, the angle of the magnet 22 provided on the swing shaft 21 side of the swing rod 11 changes. Therefore, a change occurs in the signal output from the Hall element 31 of the circuit unit 30 provided outside the fuel tank Q, and the liquid level is detected from this change.

  It should be noted that the present invention is not limited to the illustrated configuration, and the design can be freely changed without changing the gist of the present invention. Moreover, the usage example of this invention is not limited.

Q Fuel tank 10 Float 11 Oscillating rod 12 Float 20 Mechanism unit 21 Oscillating shaft 22 Magnet 23 Protective cover 30 Circuit unit 31 Hall element 32 Substrate case 33 Substrate

Claims (3)

In a fuel liquid level sensor that detects the liquid level with the vertical movement of the float installed inside the fuel tank,
A mechanism part is provided by a swing shaft that pivotally supports the swing rod of the float and a magnet provided at the swing rod end of the swing shaft side,
A circuit unit is provided by a substrate installed outside the fuel tank and a hall element attached to the substrate,
A fuel level sensor characterized in that the mechanism is installed inside the fuel tank, and the angle of the magnet linked to the float is detected by the Hall element of the circuit installed outside the fuel tank. .   The said mechanism part is installed in the said fuel tank in the state accommodated in the protective cover, The said circuit part was installed in the exterior of the said fuel tank in the state accommodated in the substrate case. Fuel level sensor.   The fuel level sensor according to claim 2, wherein the protective cover and the substrate case are formed of a resin excellent in oil resistance and sliding property.

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